Abstract: An acoustical panel for reducing acoustic noise is disclosed. The panel is comprised of a corrugated sheet of material. The sheet of material has a generally parabolic-sinusoidal configuration forming a plurality of corrugations. The corrugations extend in a first direction and form a plurality of peaks and valleys. At least one side of the panel has a surface adapted to face a source of acoustical noise. The surface acoustically diffuses acoustic waves striking the surface and causes acoustic wave interference to occur. The acoustic panel has a transaxial stiffness-compliance such that the panel is permitted to pump when low frequency acoustic energy is applied to the panel for the purpose of dissipating acoustic energy.